Means for projecting and magnifying tuning indicia



Dec. 28, 1937. L. McWEENY 2,103,333 MEANS FOR PRQJECTING AND MAGNIFYING TUNING 'INDICIA V Fi led Nov. 12, 1936 Mg; K

E t V v b m 7 3E Patented Dec. 28, 1937 D v i UNITED STATES P ATENT OF'FlCEf MEANS FOR PROJECTING AND MAGNIFY- ING TUNING INDICIA iIohn L. McWeeny, Chicago, 111. Application November 12, 1936, Serial No. 110,461 3 Claims. (01. lit-124.4

My invention relates to radio receivers and standing the greatest care in construction and particularly to means for facilitating the applyassembly, a variation in either or both the in ing and reading of-the indicia on the tuning ductance or the capacity in the circuit. Inprac- .dials thereof. tice itii's customary to calibrate a small number Where the indicia, such as kilocycles or station of instruments, then take the average thereof identification letters, are intended to be read diand provide a dial that will approximate the rectly from a dial, thesize of the figures or letcorrect reception of the frequencies 'within the ters must be relatively small unless a dial is'used range. In the chassis subsequently produced of inconveniently large size. To obviate this dii there may be substantial accuracy at somepoints in ficulty I provide a dial of convenient size located on the dial and radical departure therefrom at within the radio cabinet and provided with m other points. w l dicia, preferably printed inreverse. Ithen mount Furthermore, {it is impossible to provide an a lamp in such position that rays of light are accurate dial even though each individual cir-- projected through the openings corresponding cuit is calibrated atthe factory, a practice that t0 the letters ures. the rays being collected would very largely increase the cost and render 15 by a lens and by it projected onto a screen in commercial production impossible; this for the position to be easily read by the user of. the radio reason that changes take place after manufacture, V apparatus. Thus a large number of relatively due to adjustment of intern'al'stresses in the man minute letters or'figures may be placed on a terials, changes of temperature, etc.,andastrictly comparatively small dial, the projection, howaccurate calibration is only possible after an ever, being as large as desired. individual receiving set has been located at the In adapting apparatus such as thisto modern point of use and has become acclimated. radio receiving sets, means are rcessary for The apparatus here disclosed adapts itself to correlating it to the adjustments that provide the last named operation and consequently to for tuning in various bands; that is, different the production of an instrument in which the wave lengths. In order to adapt'the receiving dial indications are strictly accurate. It is a setfor reception of signals of varying wave known fact that few users are interested in the lengths,a sc -called band switch is employed and reception of programs from more than a dozen in my apparatus I provide a connection between f stations or thereabouts. In carrying out my idea, the band switch and the tuning dial, the dial it is preferable that the disc for carrying the 30 having thereon indicia arranged in concentric indicia should be composed of transparent or circles representing stations in the different translucent material and should carry a numbands. Thus the device automatically adapts ber of bands,'each roughly calibrated to show itself to the different adjustments and the user approximate frequencies in wave lengths in kilocannot make an error. I cycles, meters or megacycles, the arrangement Preferably, the individual designations are arbeing such that a continuous open space remains ranged radially of the dial and the light and within thebands'. The purchaser willbe' furlens are located at a 'point parallel to a transnished with a strip or sheet containing the verse horizontal line through the axis of the punched designations of the larger or more im- 1 40 disc. When so arranged the disc is mounted for portant stations, the individual designations be- 40 horizontal adjustment to accommodate the difing adapted to be clipped oifand adhesively ferent bands. With this arrangement the inapplied to the correct point on the dial when the dicia is displayed horizontally and will fade out instrument has been tuned to that station. If and in from the top and bottom of the screen desired, the designations may be identified as to on which it is displayed. size, class or location by means of colors. 45

' The apparatus herein disclosed is constructed The invention will be more readilyunderstood in the light of therecognition of certain inherent by reference to the accompanying drawing; in weaknesses in the system of radio construction which, in present use. Fig, 1 is a perspective view, diagrammatical in It is virtually impossible in the commercial form, showing the described improvement as 50 production of radios to produce two or more applied toa radio chassis; and, consecutive chassis in which the calibrations Fig. 2 is. an enlarged fragmentary elevation of indicated on the selection dial are accurate as an the dial.

indication of the frequency or wave length of In the drawing I have indicated a radio chassis a signal that is received. There will be, notwithat III on which a variable condenser H is mounted, 55 I the condenser having an operating shaft l2. A tuning shaft II has a pinion ll thereon engaging a large gear I! fixed to the shaft H. A pinion It in mesh with the gear It carries a flexible shaft I! that engagesthe shaft It on which a dial I9 is mounted.' The bearing 20 for the shaft i8 is mounted on a carriage 2i supported on rods 22,

the carriage being movable horizontally by means of the metal belt 23; This belt passes over suitable antifriction rollers and is driven by a sprocket 24 fixed on a flat shaft 25 which constitutes the shaft for actuating a band switch 26. Thus as the band switchis turned to adapt the instrument for the reception of different frequencies the dial is is shifted in order to present diflerent concentric circles bearing the station call letters or wave lengths to the light projecting apparatus.

- The specific construction of the dial is best illustrated in Fig. 2 in which the customary bands ar provided, the approximate calibration in wave lengths being indicated by the figures atthe lines intervening between the hands. This will I leave spaces 21 that are open and are adapted to receive pieces of paper 28 or similar material that may be adhesively secured to the disc. These pieces will be punched or otherwise marked in such manner that light will be projected through tin: designated characters thereon. In practice the user or dealer will accurately determine the correct tuning position for various stations and apply the designations in the described manner. The'number of different bands is a matter of selection, depending on the capacity of the instrument.

The meansfoivisualizing the tuning of the instrument comprise a light 29, the rays from which are projected by means of a reflector 30 through a diffuser 3i thence through the disc with its indiciathereon, the rays passing through the disc being collected by a lens 32 and projected onto ascreen 33 'of ground glass or similar material, carried by the case of the instrument.

According to. the design, the image may be enlarged to the extent desired. Where the indicia is in the form of reverse printing; that is, with opaque material surrounding the outline of .the letters or figures, the light will be projected only through the outlines and the screen will be dark in the spaces surrounding said 'outlinesjif the indicia is applied in the form of direct printing the reverse will be true.

venience we have shown the indicia on the screen.

For con- 33 in the form of direct printing.

It will be noted that the indicia is readable radially of the dial and the light projecting app 'ratus is placed at a point adjacent to a line through the transverse horizontal axis of the disc. This enables the application of. a larger .denser, said disc having a plurality'of series of indicia arranged in circles of different radii, said indicia beingradially disposed in light-contrast relation on said disc, a source of light positioned to project rays pastsaid'indicia, a lens placed to i collect said transmitted rays, 9. screen, on which said rays are projected to reproduce said indicia in enlarged form, and means for shifting said disc to present the indicia of different circles to said source of light.

2. In a radio receiving set, the combination with a variable condenser of a disc mounted for bodily horizontal movement transverse to the axis of rotation of the disc, a flexible shaft connecting the shaft of the disc to the rotating element of the condenser, said disc having a pluralityof series of indicia arranged in circles of different radii, said indicia being radially disposed in lightcontrast relation on said disc, a source of light positioned at a point adjacent to a horizontal line through the rotative axis of the disc whereby to project rays past said indicia, a lens placed to collect said transmitted rays, a screen on which 'said rays are projected to reproduce said indicia in enlarged form, and means for shifting said disc horizontally to present the indicia of different circles to said source of light.

3. In a radio receiving set having a variable condenser and a band switch, the combination of a disc rotatively mounted with capacity for bodily movement transversely of the axis of rotation, a

flexible shaft connecting the rotating element of the condenser to the shaft of the disc, said disc each series being circularly arranged and of different' radius, a source of light placed to project rays through said disc past said indicia, a lens to collect said rays, a screen on which said rays are projected in enlarged size and a connection between the band switch and the disc whereby said disc is shifted to present anothercircle of indici when said band switch is actuated.

JOHN L. MCWEENY.

having a plurality of series of indicia thereon, 

